Hand-operated, or walk-behind, snowthrowers can be classified as either single stage or two stage devices, depending on the number of snow handling implements (e.g., impellers or fans). Thus, a single stage snowthrower includes a single rotating impeller whereas a two stage snowthrower typically includes a first auger stage and a second high speed fan stage, wherein the auger engages the snow and conveys it to the fan which throws the snow at high speed up and away from the snowthrower.
Although single stage snowthrowers are generally lighter, less expensive and intended for smaller tasks, both types of snowthrowers have common features. For example, each type of snowthrower typically includes a housing mounted on wheels or tracks for movement along the ground. The lower forward portion of the housing is open and contains one or both of the snow handling implements. Mounted to the housing and operatively coupled to the snow-handling implement(s) is a prime mover such as a gasoline engine or electric motor. Extending upwardly from the housing is a handle having an upper end located at a convenient height for the operator.
Single stage and two stage snowthrowers also include some type of adjustable snow deflecting device, e.g., a chute, deflector, or set of vanes, which selectively directs the thrown snow either forwardly or to one side or the other of the snowthrower. Typically the deflecting device, henceforth called the "chute" for convenience, is connected to the housing toward the top of the housing opening which contains the moving snow handling implement(s). As will be described further below, the present invention particularly concerns the chute and its interconnection with the snowthrower housing.
Recent attempts have been made to construct snowthrowers, particularly single stage snowthrowers, such that they can be rendered quite compact when not in use. There are several reasons for this trend, including the fact that snowthrowers are relatively expensive, and many consumers desire a portable machine which they can easily transport to various sites rather than one machine at each site. It is also desirable to have a snowthrower which can be easily folded or disassembled into a very compact state for storage purposes. From the manufacturers' standpoint, a machine which can be easily disassembled, folded, or generally made more compact is desirable since it can be shipped and stored in a smaller container and a single truck can carry more machines.
Prior art snowthrowers have certainly addressed the "compactibility" problem discussed above. In fact, many prior art snowthrowers include two-piece folding handles which have a lower handle portion connected to the housing and an upper portion pivotally connected thereto wherein wing nuts or thumb screws or the like are used to interconnect the two handle portions.
In addition, some very large snow excavating machines, not of the hand-operated or walk-behind type, have included folding or collapsible discharge chutes. See U.S. Pat. Nos. 4,312,143 and 4,184,274, for example. Such chutes are often provided so that the vehicle carrying the snowthrower unit can be garaged in normal fashion and can pass under low bridges. Although folding or collapsible chutes indeed render a snowthrower more compact or compactible, they also tend to greatly complicate the chute, add expense and weight to the snowthrower, and are generally inappropriate for use on small walk-behind snowthrowers.
Some prior art walk-behind snowthrowers have even included removable chutes, although not for the sake of compactibility. For example, reference is made to U.S. Pat. No. 2,536,166 which shows a chute which can be removed and reconnected to the housing to allow for adjustment of the chute relative to the housing. While at first glance this type of design might seem to adequately address the compactibility problem discussed above, it in fact is inadequate because it allows the chute to be easily removed without tools, thus posing a potential safety hazard. Such removable chutes also do not meet the currently-applicable ANSI standard B71.3-1984, Section 5.2, which indicates that all guards, shields, guides, and deflectors should be designed so that they cannot be removed from the machine without tools. Although it is not necessary that snowthrowers meet this ANSI standard, it is thought to be generally desirable.
The present invention addresses the snowthrower compactibility problem discussed above, and in particular is directed toward a removable snowthrower chute which complies with the aforementioned ANSI standard and which does not present a hazard of any type.